Article 4 Manner of service of questions and replies
A question to the respondent may be served on him—
(a)
by delivering it to him; or
(b)
by sending it by post to him at his usual or last known residence or place of business; or
(c)
where the person to be served is acting by a solicitor, by delivering it at, or by sending it by post to, the solicitor’s address for service.